Frequently, excessive voltage or current is applied across service lines that deliver power to residences and commercial and institutional facilities. Such excess voltage or current spikes (transient overvoltages and surge currents) may result from lightning strikes, for example. The above events may be of particular concern in telecommunications distribution centers, hospitals and other facilities where equipment damage caused by overvoltages and/or current surges and resulting down time may be very costly. Typically, sensitive electronic equipment may be protected against transient overvoltages and surge currents using surge protective devices (SPDs).
Overvoltage protection devices, circuit breakers, fuses, ground connections and the like are often mounted on DIN (Deutsches Institut für Normung e.V.) rails. DIN rails may serve as mounting brackets of standardized dimensions so that such electrical control devices may be sized and configured to be readily and securely mounted to a support surface such as an electrical service utility box.